Lathe transmission and control mechanism



March 13, 1951 H. J. SIEKMANN ET AL 2,545,053

LATHE TRANSMISSION AND CONTROL MECHANISM iled Feb. 26, 1948 aSheets-Sheet 1 INVEN TORS HAROLD J. S/E/(MAN/V GEORGE J.KA5SELMANIVATTORNEYS.

March 13, 1951 H. J. SIEKMANN ET AL 2,545,053

LATHE TRANSMISSION AND CONTROL MECHANISM 8 Sheets-Sheet 2 Filed Feb. 26,1948 l lllll llllllllll'" INVENTORS. HAROLD J. S/E/(MA/VN M W u. 8 J M mH ATTORNEYS.

March 1951 H. J. SIEKMANN 'ET AL 2,545,053

LATHE TRANSMISSION AND CONTROL MECHANISM Filed Feb. 26, 1948 8Sheets-Sheet 3 IN VEN TORS.

HAROLD J. \SIEKMANN GEORGE J. KAS-SELMA/VN WYM A TTORNEYS.

March 13, 1951 Filed Feb. 26, 1948 H. J. SIEKMANN El AL LATHETRANSMISSION AND CONTROL MECHANISM FIG.5

8 Sheets-Sheet 4 IN VENTORS'. HAROLD J. S/EKMA/VN BY GEORGE J.KASSELMANN ATTORNEYS.

March 13, 1951 Filed Feb. 26, 1948 LATHE H. J. SIEKMANN ET ALTRANSMISSION AND CONTROL MECHANISM FIG.6

8 Sheets-Sheet 5 IN VEN TORS. HAROLD J. S/EKMANN GEORGE J. KASSELMA/VNATTORNEYS.

March 13, 1951 H. SIEKMANN ET AL 2,545,053

LATHE TRANSMISSION AND CONTROL MECHANISM Filed Feb. 26, 1948 8Sheets-$heet 6 1N VEN TORS HAROLD J. S/E/(MANN BY GEORGE J.KA$$ELMAIVNATTORNEYS.

March 13, 1951 H. J. SIEKMANN ET AL 2,545,053

LATHE TRANSMISSION AND CONTROL MECHANISM Filed Feb. 26, 1948 8Sheets-Sheet '7 133 120a gm {as FIG.|2

IN VEN TORS HAROLD J. SIEKMANN GEORGE J. KASSELMANN ATTORNEYS.

March 13, 1951 H. .1. SIEKMANN ET AL 2,545,053

LATHE TRANSMISSION AND CONTROL MECHANISM Filed Feb. 26, 1948 8Sheets-Sheet 8 MOTOR HORSE POWER rv u: -P

m SPINDLE SPEED R.P.M.

F G. I7 INVENTORS.

HAROLD J. SIEKMANN BY GEORGE LKASSELMANN MVW ATTORNEYS.

Patented Mar. 13, 1951 LATHE TRANSDIISSION AND CONTROL MECHANISM HaroldJ. Siekmann and George J. Kas's'clma'nn, Cincinnati, Ohio, assignors toThe R. K. Le

Blond Machine Tool Company,

Cincinnati,

Ohio, a corporation of Delaware Application February 26, 1948, SerialNo. 11,274

9 Claims (01. 74-472) This invention has to do with lathes'and isconcerned primarily with the transmission which delivers power to thespindle and certain control mechanism associated therewith.

In the patent to Groene No. 2,419,639, there is illustrated anddescribed a tool room lathe having a transmission and associated controlinstrumentalities of the same general type as provided by thisinvention. However, this invention contemplates certain improvementsover the machine of this patent.

In .the Groene patent referred to, an electric motor is used as the maindriving element. This motor is controlled by certain electronic devicesso as to provide an infinite number of speed variations over the rangeof the motor. Moreover, provision is made for driving the spindle overits high range of speed by a direct belt drive from the motor. Inaddition, a back gear drive is provided which affords a gear reductionbetween the motor and'the' spindle. Either the direct belt drive or theback gear drive is used selectively, depending upon the character of theWork which is being performed.

While a lathe which includes a transmission of the type aforesaid hasmet with a large degree of satisfaction, still it is felt that there iscertain room for improvement. It is noted that the electronic devicesfor controlling the speed of the motor are so costly as to render theiruse impractical for installation under many circumstances. Furthermore,when the motor is operating under low speed in either the direct beltdrive or the back gear drive,'there is a marked falling off of thehorsepower that is developed.

With the foregoing conditions in mind, the present invention has in viewas an important objective the provision of a lathe of the type indicatedwhich includes a variable speed direct current motor that is driven froma motor generator set. Thus the motor generator set and associatedelectrical instrumentalities take the place of the electronic devicesheretofore used for this purpose with a material saving in costresultingfrom the change.

Still another highly important object of the invention isthe provisionof a lathe of the character aforesaid which includes a transmission fortransmitting power from the motor to the spindle and which transmissionaffords three speed ranges.

More in detail, the invention has as an object the provision in a latheof a transmission including adirect belt drivefor the high speed range,a high back gear drive for an inter-ma F diate speed range, and a lowback gear drive for a low speed range. The variable speed motor iseiie'ctive to afford a large number of speed variations over each range.The main advan* tage which is attributed to this arrangement is that thetotal part of the entire operating range in which the developedhorsepower falls oif is materially reduced.

In a lathe of the type with which this inven tion is concerned such asdisclosed inthe said Greene patent, provision is made for the cuttingof'coarse threads. When the lathe is so used,

the transmission of power to the tool feed must include a comparativelyhigh increase in the ratio at which the feed is driven. In the saidpatent, certain gear trains including shiftable in accordance with theabove announced obj 'e'ctsj,

it is, of course, necessary to combine a rheostat with the motor andthis rheostat' is adjustable so as to give the varying speeds. From theView point of safety and preventing damage to the mechanism, it isdesirable that any change in the effective transmission drive takeplace" only when the rheostat is adjusted to a low speed. With thisthought in mind, another object of this invention is the provision of aninterlock which is effective to permit the gears to be shifted" onlywhen the rheostat has been adjusted to low speed. Themanner in whichthis end is attained will also become apparent as the specification .develops.

Not only is it necessary to provide a lathe which will include thevarious devices and mechanisms essential to following the above outlinedobjectives but it is equally important that indi-- cating mechanism beprovided which accurately informs the operator of the speed at which thespindle is rotated. Indicating mechanism of this general character isillustrated and described in the said Groene patent,

certain novel dial mechanism is provided as an important part of theinvention.

As there are three speed ranges provided for by the transmission, a dialof 360 degrees is divided into three sections of 120 degrees each, therebeing a section for each speed range. A gear shift lever is so connectedto this dial by appropriate gearing that upon movement of the lever toeffect a change in the driving ratio the dial is rotated to bring thecorresponding dial section to the top which is the effective position.

Cooperating with this dial is a pointer or indicator mounted on arotatable disc. This pointer is movable over an angular distance of 120degrees so that it complements the particular dial section at the top togive an effective reading. Obviously, this dial or marker moves onlythrough 120 degrees. However, it is important that the operating memberwhich adjusts the rheostat be movable through a full 360 degrees so asto provide for accurate and not too rapid adjustment. Thus, a furtherobject of the invention is the provision of operating connectionsbetween the rheostat and operating member and the pointer which providefor a l to 1 ratio between the operating member and the rheostat but a lto 3 ratio between the operating member and the pointer. This isaccomplished by a gearing arrangement to be described in detail in theensuin specification.

Various other more detailed objects and advantagesof the invention suchas arise in connection with carrying out the above noted ideas in apractical embodiment will in part become apparent and in part behereinafter stated as the description of the invention proceeds.

The invention therefore comprises a lathe including a variable speedmotor driven by a motor generator set and which in turn drives a spindlethrough any of the three drives provided by a novel transmission.Certain interlocks and indicating devices are associated with thetransmission and included as a part of the invention.

'. For a full and more complete understanding of the invention,reference may be had to the following description and accompanyingdrawings wherein:

1 Figure 1 is a view in front elevation with parts broken away to showthe arrangement of certain electrical instrumentalities of a latheincluding transmission and control mechanism designed in accordance withthe precepts of this invention.

4 Figure 2 is a view in front elevation of the headstock and on anenlarged scale as compared to Figure 1'.

Figure 3 is an enlarged detailed view of the gear shift lever and dialassociated therewith.

Figure 4 is a view taken as a vertical section normal to the spindle.This view is taken about on the plane represented by the line 44 ofFigure 2.

Figure 5 is another vertical section taken normal'to the axis of thespindle and is taken about on the plane represented by the line 55 ofFigures 'l and 6.

' Figure 6 is a compound sectional view developing the various operatingaxes and is taken about on the planes represented by the lines 6-45 ofFigure 5.

Figure 7 is an enlarged detailed view, partly in section and partly inelevation, of the connections between thecontrol mechanism and therheostat'at the rear of the head. This view is taken about on the planerepresented by the line l---'! of Figures 8 and 9.

Figure 8 is an enlarged detailed sectional view taken about on the planerepresented by the line 8-8 of Figure 7.

Figure 9 is another enlarged detailed sectional view taken about on theplane represented by the line 9--9 of Figure 7.

Figure 10 is a detailed view taken from the rear of the head with thecasing removed and showing in detail a part of the interlock whichprevents the gears being shifted until the rheostat is adjusted to lowspeed. This view is taken about on the plane represented by the line !E!-l B of Figure 11.

Figure 11 is a detailed horizontal section being taken about on theplane represented by the line I I| I of Figure 10.

Figure 12 is a detailed plan view on an enlarged scale of a certain partof the gear shifting mechanism.

Figure 13 is an enlarged fragmentary sectional view taken on the lineI3-l3 of Figures 3, 14, and 15 showing the dial pointer and associatedoperating instrumentalities.

Figure 14 is an enlarged sectional View of the indicator mechanism beingtaken on the plane represented by the line I il4 of Figure 13.

Figure 15 is an enlarged sectional view taken normal to the axis of theoperating shaft and is taken about on the plane represented by the line15-45 of Figure 13.

Figure 16 is an enlarged detailed plan view showing the shiftingmechanism for changing the drive to the feed for coarse thread cutting.

Figure 17 is a graphical illustration showing the power output over theoperating range provided by the motor and transmission hereof.

Referring now to the drawings wherein like reference characters denotecorresponding parts, the manner in which the above outlined ideas areincorporated in a lathe will be described.

General arrangement Figure 1 illustrates a lathe which may be typical ofthe type to which the present invention is adapted. Such a lathecomprises a bed 20 which is supported by legs 2| and 22, the leg 2|being located at the tailstock end and the leg 22 at the headstock.Upstanding from the bed 20 is the tailstock which is referred togenerally as 23 while from the opposite end upstands the headstock 24.

An apron 25 is shown as being positioned intermediate the headstock 24and tailstock 23 and this apron carries a cross slide 26 which in turncarries a tool post represented at 21. The above noted elements arecommon to all lathes and are described purely for the purposes ofindicating the environment; of the present invention.

Below the bed 20 there is a motor generatorset which is shown in brokenlines in Figure 1 and which is designated Zia. The motor of this set isadapted to take current from an AJ C.

source of supply which is convenient to the lathe.

As a practical matter, such a source of supply will most likely be athree phase, 60 cycle current under a voltage of either 220' or 440volts as that is the type of current most commonly available around theplaces where lathes of this type are used. The motor of the unit 21adrives the generator which provides current for a main driving motorrepresented at 22a. This motor 22a is a Variable speed direct currentmotor. Thepanel represented at 20a is shown as being adapted to carryvarious electrical devices which are used in conjunction with the unitMaand motor 22a. The various elements and make up of the electricalequipment itself is not a part of the present invention because it ispurchasable as such from any of the various manufacturers of electricalequipment of this type. The only thing with which the present inventionis concerned is that the motor 22a may be adjusted to provide varyingspeeds in its output shaft and this is accomplished under arrarrangement in which the voltage of the armature circuit is varied.However, the invention is not to be limited in this respect as thevariable speed on the part of the motor 22a could be provided for inother ways. Moreover, the design of the motor 22a itself is not a partof this invention as it is purchased as such from a manufacturer ofelectrical equipment.

The center of the work spindle isshown at 24c in Figure 1 while thespindle itself is indi cated at 24a in Figure 6. This spindle 24acarries. the usual work fixture indicated at 241) and shown in bothFigures 1 and 6. The motor 22a has an output or drive shaft 22b and thespindle a is driven from this shaft 22b. Upon referring to Figure 4 itwill be noted that the motor shaft 221). drivably carries a pulley- 22c,the driving relation being established by a key 22d. A back gear shaft,28 (see Figures 4 and 6) driv ably carries a pulley 28a, the drivingrelation being established by the keyshown at 29 and the spindle 24acarries a pulley 30 which in some conditions is journaled for freerotation about the spindle and in other conditions is clutched thereto,Belts 3i pass over the pulleys 220, 28a, and 30 and guide roll 32 in themanner shown in Figure 4 and these belts serve to transmit the power forrotating the spindle 24a. This same setup also provides the power foroperating the fine tool feed as will be later described.

Transmission The transmission of this invention is intended to providethree speed ranges. The highest of. these ranges is the. direct beltdrive from the motor shaft 22b to the spindle 24a. and, is accomplishedby clutching the pulley 30: to the spindle 24a while the other gears,are ineffective. The intermediate speed range is provided by the highback gear drive and the lowest range by the low back gear drive.

Asshown in Figure 6, the pulley 30 is journaled on the spindle 24a bybearing assemblies. 33'. A clutch member 34. is journaled in a wall ofthe headstock such as represented at 35 by bearing assemblies 35. Thisclutch member 3.4 is keyed tothe spindle 24a by thekey shown at 31.; Theclutch member 34. carries, a plurality of pins, one of which isshown, at3,8,, and which pins are slidable intheclutch, member in a directionparallel. to the axis of the, spindle. Each of'the pins 38 has a headat. 33 which provides for its connection to a shifting collar that is.sli'dable on the spindle 24a. The collar 40 has-a groove M whichreceives the opposite ends of a shifting yoke that is shown at 42 inFigure 5. The ends of the pins 38 remote from the heads 39 take the formof points which are adapted to be received in openings formed in a plate43 that is drivably carried by thev pulley 30. Thus, when the pins 38engage the openings in. the plate 4.3 the driving relation between thepulley 33 and spindle 24a is established. On, the other hand, when thepins are disengaged from these openaenrose ings, the pulley 3D is freeto rotate about the spindle.

Positioned between the back gear shaft 28 and the spindle 24a are a pairof aligned shafts 44. and 55. The shaft 44' has its outer end journaled'in the wall 35 by a bearing assembly shown at 46. The inner end of theshaft 44 is journaled in a bearing 4? carried by a Wall 48 formed in theheadstock 24. The shaft 45 has its inner end journaled in a bearing 49carried in the wall 4'8 and its outer end journaled in a bearing 50 carried by the wall 48a of the headstock 24.

A compound gear 5-! carrying a gear 52 at one end and a pini0n53 at theother is slidable on the shaft 45 and is keyed thereto by the key shownat 55. In one position of the compound gear 5| the pinion 53 is adaptedto mesh with a gear 55' that is keyed to the spindle 24s as shown at 58.The gear 52 meshes with a pinion 51 that is keyed to a sleeve 58 that isjournaled on the back gear shaft 28. It is notable that this: engagementof the gear 52 and pinion 51 takes lace in an positions of the compoundgear 5i.

The back gear shaft 28 is journaled in the headstock wall '35- b thebearings shown at 59- and 60. A part of this shaft 2-8 i splinedas shownat El and slidably mounted on this splined part is -a gear 62. This gear6-2 has an extension formed with a groove 63 which receives one end of ashifting arm that is shownin broken lines in Figure 5 at 64 and also inFigure 12. A pinion 65 is keyed to the shaft M as indicated at 56 andthis pinion is slidable on the shaft. A gear 61 is in turn keyed to thepinion 65 as shown at 58 and is movable 0n the shaft 14. The unitcomprising pinion and gear iii is adapted to be shifted longitudinallyon the shaft M- by a shifting member shownat 59 in Figures 5 and 12. Themember 69 is formed with a slot which receives the gear 61 and iscarried at one end of an arm 10.

The sleeve 58 which, it will be recalled, is journaled on the back gearshaft 28, the bearings being shown at H, carries at its forward end anexternal gear 12 and an internal gear 13. The internal gear 13 isadapted to mesh with the pinion 62 while th external gear 12 is adaptedto mesh with the pinion 65.

Before describing the manner in which the shifting of the several gearsis accomplished, it is noted that when the pinion 62 meshes with theinternal gear 13 and the pinion 53 is engaged with the gear 55, thedrive is from the pulley 28a through the shaft 23, gears 62 and 13-,sleeve 58, pinion 5?, gear 52 of th compound gear 51-, pinion 53 andgear 55' to the spindle 25 a. Underthis condition, the pulley 30' is, ofcourse, not clutched to the spindle 24a but merely journals freelythereabout. This is the intermediate range or high back gear speed.

In low back gear, the pinion 53 and gear 55 are still engaged but thegear 6'2 is shifted so that it engages the gear 6! rather than theinternal gear 13. At the same time, the unit made up of pinion 65 andgear 67 is shifted so that the pinion 65 meshes with the gear- 72-. Thedrive is now from pulley 28a through shaft 28, gear 62, gear 6.1",pinion 65, gear 12, sleeve 58, pinion 5?, gear 52 of the compound gear5|, pinion 53, and gear 55 to the spindle 24a.

Shifting mechanism.

Upon referring to Figure 5 it will be noted that a sleeve '14 isjournaled in the upper part of the headstock 24 in a directiontransverse to the axis of the spindle 24a. A gear shift lever 15 isdrivably connected to this sleeve in a manner to be later described. Theimportant thing for the moment is that swinging of the lever causesrotation of the sleeve it to shift the gears and clutches so as torender any range desirable effective.

As above explained, the yoke 42 engages the groove 4| of the shift ringat. This yoke 42 is carried by a sleeve 76 that is slidable on a rod 1'!mounted below the sleeve l4 and in a direction transverse thereof. Aring i8 is drivably carried by the sleeve M and has gear teeth asindicated at 19 which engage complemental teeth on the sleeve 76. Thus,as the sleeve '54 is rotated the ring 18 is rotated and the engagementof the teeth H! with the sleeve 15 causes the latter to slide along therod 11 and impart a corresponding rectilineal movement to the yoke 42.This arrangement is quite similar to that described-in the aboveidentified Groene patent.

Slidable on a rod 30 that is positioned below the sleeve 14 and whichextends in a direction transverse thereof is a shifting member 8! thatis formed with a slot which receives the gear 52. A ring 82 is drivablymounted on the sleeve l4 and has teeth at 83 which engage complementalteeth on the member 8!. Thus, as the sleeve M is rotated, the ring 82 isrotated and the teeth 83 cause the member 8i to slide along the rod 80.As the gear 52 is engaged by this member 8|, a corresponding movement isimparted thereto.

Referring now more particularly to Figure 12 which will be considered inconjunction with Figure 5, it will be noted that the sleeve '54 drivablycarries a ring 84 which has formed in it a cam slot 85. A roller 88 isreceived in this cam slot 85 and is carried on a pin Bl which is in turncarried by an arm 88. remote from the roller 86 is drivably connected toa vertically extending shaft 89. Thus, as the ring 84 is rotated, thecam slot 85 affects the roller 86 to cause a swinging of the arm 88about the shaft 89 as an axis. It will be recalled that the arm itcarries the member 69 which is formed with a slot that receives the gear6'3. This arm is also drivably connected to the shaft 89. The arm 64 isalso drivably connected to the shaft 89 and at its free end carries ashoe fill which is received in the groove 63. It is therefore evidentthat as the sleeve M is rotated the cam ring 84 and arm 88 impart acorresponding rotating motion to the vertical shaft 89-. This causes arocking of the arms 64 and ill to move the gear B2 in one direction andthe gear 61 in the opposite direction. Thus, when the gear 62 is movedinto mesh with the internal gear E3, the unit made up of pinion 65 andgear 6'! is moved in the opposite direction causing the pinion 65 tobecome entirely free and clear of the external gear 12. Then again, whenthe pinion $2 is shifted into engagement with the gear E7, the lattermoves as a unit with the pinion 55 to cause the pinion 65 to mesh withthe gear l2.

Control and indicating mechanism It will be noted from Figure 5 that thesleeve 14 encloses a shaft 9!. Both the sleeve 14 and shaft 9! extendsubstantially across the headstock at the top. The mechanism andarrangement at the rear of the headstock is shown in Figures '7 to 11,inclusive. Upon referring to Figure 7 it will be seen that a rheostat isrepresented at 9.2, It is this rheostat that controls the speed The endof the arm 88 at which'the motor 22a operates.- Extending iriwardly fromthe rheostat 92 is a control shaft 93. Drivably carried by the shaft 93is a gear 34 with which meshes an idler gear 95. A second gear 96 mesheswith the idler gear 95 and is drivably carried by the shaft 9 I At thispoint, it is well to note that the gears 94 and 98 are of substantiallythe same diametrical dimensions so as to provide for a 1 to 1 ratiobetween the A disc This disc 91' is formed with three openings I02,

Hi3, and 104. Any of these openings is adapted to receive the head m5 ofa pin ills-which is carried by a disc it! that is keyed to the sleeve Mas indicated at Hit. It is evident that when the head N is received inany of the openings )2. E98, or Hit, the sleeve i l cannot be rotated.Thus, when this engagement is maintained there can be no shift in thetransmission from one speed range to another. In order to permit such achange, it is necessary that the shaft 9| be moved laterally within thesleeve it so as to move the discs! away from the pin "35. This may beaccomplished by the operator pressing against the button shown at 10-9providing the rheostat 92 has been adjusted to low speed.

It will be noted that the gear 96 which is pinned to the thimble S8 andshaft iii by the pin shown at [it is formed with a socket Ill. Theframework 35 carries a panel H2 and extending inwardly from this panelis a pin i It, the free end of which is positioned in close proximity tothe face of the gear 86. Thus the only position in which the shaft 9!and gear 98 which is carried thereby may be moved inwardly is when thepin 5 l3 aligns with the socket l l i. This condition of alignmentobtains only when the rheostat 92 is adjusted to low speed as determinedby the position of the gear 96.

.. the position depicted in Figure 7.

It will be noted that theshaft 9| has a reduced end portion l M and theend portion of the latter is slidably received in an opening H5 formedin the panel l H, An expansion coil spring I it is disposed about thisreduced portion IM and noted that the gear shift lever l5 cannot bemoved to shift gears unless the disc 9'5 is withdrawn from the head I65of the pin Hi6. That is,

there cannot be a shift in the gear ratio without first pressing againstthe button I09. But the latter operation is not possible of attainmentuntil the rheostat 92 has been adjusted to low speed so as to cause thepin H3 and socket ill to come into alignment.

Referring now more particularly to Figure 13' The 9 commodates relativemovement between these parts. Drivably connected to the button I89 is asleeve II9 having an inner portion that is counterbored to provide athickened portion I that rotates about another sleeve I2I held in placeby a nut I22 which is threaded on the end portion of the sleeve 14.

An operating member I23 is pinned to the sleeve I I 9 as shown at I24and presents a knurled ring I25 for the convenient grip of the operator.The sleeve I20 is formed with external gear teeth I 26 which provide ineffect a gear that is drivably connected to the knurled operating ringI25. A stationary part which is connected to the headstock 24 and whichis designated I20a carries a compound gear I21. One end of the compoundgear I21 takes the form of a pinion I28 that meshes with the gear I26while the other end takes the form of a pinion [29 that meshes with areversing pinion I29a (see Figure 14') which in turn meshes with aninternal ring gear I30 formed as a part of an indicating ring I3I. Thelatter is formed with a lip I32 that overlies the .stationary part 120a.At an appropriate point on the outer periphery of the ring I3I, it isprovided with a line or pointer designated I33. Thus, it is evident thatas the ring I25 is rotated, the shaft is turned and the rheostat 92adjusted with a 1 to 1 ratio obtaining between the control shaft 93 ofthe rheostat and the operating ring 125. However, due to the gearreduction provided by gears I25, I28, I29, I29a. and I38, the ring I3Iis driven at a lto 3 ratio, that is, it only moves through one-third ofthe angular distance through which the ring I25 is turned. This willbecome important for a matter now to be described.

The gear shift handle 15 has a reduced end which is received in a socketformed in a ring I 34.

The latter is keyed to the sleeve 14 as shown at I35 so that as thehandle 15 is swung the sleeve 14 is rotated. A circular plate I36 isanchored to the framework of the headstock by screw bolts shown at I31.A stationary gear I38 is in turn secured to the outer face of the plateI36 by pins shown at I39. Meshing with the gear I38 is a gear I46 thatis formed integrally with a stud I4I which is journaled in the ring I34.This stud .I 4| has a reduced end I42 to which is drivably connected, asby a pin I43, a gear I44. The gear I44 meshes with another gear I45 thatis carried on a sleeve I46.

A dial I41 is drivably connected to this sleeve I46 by the pins shown atI48. Thus, as the gear lever 15 is swung not only is the sleeve 14rotated but through the gears I38 and I41], stud I4I, gears I44 and I45,and sleeve 146 the indicating dial I41 is turned and the rate ofrotation is stepped up by the gearing. Under practical conditions, thegear shift lever 15 is swung through only about 85 degrees from eitherside of the vertical position dep cted in Figure 3. It is nec ssary thatthis amount of movement be effective to bring either of the threesections of th dial into the uppermost position, hence this stepped upgearing. I

Upon referring to Figure '3, it will be noted that the dial I41 isdivided into three sections. One of these is designated belt drive andwhen thespindle 24a is driven directly from the belt 3I the section sodesignated should be in the uppermost position. The high gear positionis shown at the top in Figure 3 and it is this section which cooperateswith the pointer I33 when the .high back gear ratio obtains. The lowgear section is the lowest speed provided for and it is this sectionthat should be at the top when the low back gear ratio obtains. It isevident that when the lever 15 is swung to accomplish th gear shift thedial I41 is correspondingly moved to bring the proper section of degreesto the top or uppermost position in which it cooperates with the pointerI33.

It will be noted that the stationary part I20a is carried by a pin I49that extends from the headstock 24 out through aligned slots I58 in thering I34 and dial I41.

Drive to t ol feed for course thread cutting In order to provide for theproper drive to the tool feed depending on the nature of the work, threeseparate drives to the tool fsed are included in the lathe. One of theseis the drive for fine tool feed and is effective only when thetransmission is adjusted for the high speed operation of the spindlethat is established when the direct belt drive is eifective. The seconddrive is for regular thread cutting and its operation may be establishedwhen the transmission is in either of the back gear drives. The thirddrive to the tool feed is for coarse thread cutting and may beestablished only when the transmission is adjusted to render the lowback gear drive effective.

Upon referring to Figure 4, it will be seen that .a shaft I5I hasdrivably mounted thereon a pulley I52. Another pulley I53 is keyed tothe back gear shaft 28. A belt I54 passes over the pulleys I52 and I53and serves to drive the shaft I5I. This shaft I5I is shown in Figure 6andis effective to provide the fine tool feed in the manner described inthe above identified Groene patent. Inasmuch as there is no change inthis drive from the shaft I5I to the tool feed gear which is shown atI55, it is not thought necessary to here unduly lengthen thisspecification by repeating this descriptive matter. The Groene patent isreferred to for the manner in which this is carried out. As abovepointed out, this fine tool feed .is effective only when the spindle 24ais in direct belt drive.

Certain gear mechanism is provided for establishing a drive from thespindle 24a to the tool feed and which drive may obtain when thetransmission is in either of the back gs ar ratios. This gear mechanismalso is adjustable to provide another drive for coarse thread cuttingwhich is effective only when the transmission is in low back gear drive.This is accomplished by the mechanism now to be described. A sleeve I56is keyed to the spindle 24a by the key shown at I51 and is slidablethereon due to the presence of the elongated keyway. This sleeve I56 isformed with a groove at I58 that receives a shifting member. One end ofthis sleeve I56 carries a gear I59 while the other end carries a gearI60.

A selector shaft I6I that is splined is shown as being journaled in awall of the headstock. This shaft I6I includes a part at I52 that isfree from splines and rotatably mounted on this portion I62 is acompound gear I63 providing a gear I64 and a smaller gear 1 65. The gearI64 meshes with a pinion I66 that is keyed to the shaft I5I. The gearI65 is adapted to be either engaged or disengaged from an internal gearI61 that is formed on a sleeve I68. The latter is also formed withexternal gears I69 and I111. The sleeve IE8 is also formed with a grooveI1I which receives 11' a shifting yoke at the end of an arm I16 isactuated from the sleeve 14.

It is evident that when the sleeve I 68 is shifted which to the left,speaking with reference to the 5110i ing of Figure 6, the internal gearI 61 and the gear I65 are engaged. At the same time, the gear I10 isdisengaged from the gear I69 and the gears I59 and I60 are also out ofmesh. The

drive is therefore from the shaft II through feed which is establishedwhen the spindle v is in direct belt drive.

When the sleeve I68 is shifted to the right, speaking with reference tothe showing of Figure 6, two things take place. The internal gear I61 isdisengaged from the gear I65, thereby breaking or interrupting the drivefrom the shaft I5I. As the movement is continued, the gear I 69 engagesthe gear I59, thereby driving the tool feed from the spindle 24a. Thiscondition is intended for the cutting of regular threads and...

which is established by the regular back gear or I 15 .1 variablespeed-direct current motor such as represented at 22a which will developits basic horsepower over '15 percent of its range. This means This stubshaft I 82 is journaled inthe framework and at its forward end carries anut I 33 and a pointer I64. When the adjustment is to be made for coarsethread cutting, a wrench is applied to the nut I83 to rotate the stubshaft I82. This swings the arm I80, which motion is transmitted throughthe link I19 to shift the sleeve I18 and yoke which is attached thereto.As the latter is positioned in the groove I58, the sleeve I56 isshifted.

Operational advantages It is possible and entirely practical to obtainfrom the manufacturers of electric motors a that the horsepower fallsoff over the first 5 percent of the speed range. As the lathe is set upto operate at a minimum of 6 R. P. M., at this point 3 horsepower isdeveloped. This horsepower gradually increases up to 15 R. P. M.whereupon the basic horsepower of the motor,

at its lowest speed which is established by low,

back gear. the spi dle 24a is driven by gears 55,

'53, and 52 and the spindle in turn drives the tool feed through earsI59 and I59 which latter gear meshes with the gear I12.

a coarse thread cutting, the sleeve I56 which carries a gear I60 ismoved to the left. spea ing with reference to the showing of Figure 6.It is to be remembered that this drive i to obtain only when thetransmission is in low back gear for the s indle. In such a condition,the gear 52 will have been shi ted to the right. Thus the gears 52 andI60 approach each other so as to bring them into mesh. The gear I60idles on the sleeve I56 and is driven directly from the gear 5'2. Thissame movement which brin s the gear I56 into mesh with the gear 52 alsobrin s it into meshing engagement with the gear I10. The latter beinginte ra ly formed on the sleeve I68 drives the gear I69 which mesheswith t e ear I12 which is taken as the start of the tool feed.

It is evident that as the gear shift lever 15 is turned the sleeve 14 isturned and a ring I13 which is drivably carried thereby is rotated. Thisring is formed with gear teeth at I14 that engage The a sleeve I15 whichcarries the yoke I16. sleeve I15 is slidable on a shaft I11. Thus. asthe gear shift lever 15 is shifted, the yoke I 6, which is received inthe groove I1I, shifts the sleeve I18 and gear elements carried thereby.

drive to the tool feed is from the sha t I5I but when the back gearratios are obtained it is from either the spindle 24a or the gear 52.

In order to shift the sleeve I56 to vary the ratio in this drive fromthe spindle to the tool feed. the following mechanism is employed.Slidably positioned on the rod 11 is a sleeve I18 from which depends anarm carrying a yoke that engages the groove I58. Connected to thissleeve I18 is a link I19 Which at its other end is connected to an armI80 thatextends from a hub member I8I that is keyed to a stub shaft I82.

which is 7 /2 horsepower, is developed and this condition obtainsthroughout the remainder of the range up to 60 R. P. M.

The foregoing conditions obtain-when the low back gear'drive iseffective and causes a.25 to 1 gear reduction. When the shift to thehigh back gear drive is made, the gear ratio is changed to 5 to 1. Thereis a slight gap between 60 R. P. M. and the 15R. P. M. provided by .thehigh back gear at which the developed horsepower falls off slightly to aminimum of 6 horsepower but for all practical purposes this is takencare of by the motor which, under practical conditions, will developsufiicient excess horsepower to accommodate this gap Thus, underconditions of actual usage, there is little, if any, falling off of thehorsepower in bridging the change from low back gear speed to high backgear speed.

This speed range provides for revolutions of 60 R. P. M. to -300 R. P.M. When the change is made to the belt drive, the ratio is now 1 to 1and the speed range is 300 to 1500 R. P. M. Again there is a small gapbetween 300 and 315 R. P. M. at which the horsepower may fall off sligtly but for all practical purposes this is negligible.

It is therefore evident that with the mechanism above described it ispossible to drive the spindle of the lathe over a speed range of from 15R. P. M. to 1500 R. P. M. and develop sub stantially the basichorsepower of the motor over the entire range. There is a reduction inthe horsepower from 6 R. P. M. to 15 R. P. M. and perhaps some slightreduction at the gaps indicated.

It is notable that when the direct belt drive to the spindle iseffective, the gear 62 is out of engagement with both the gears 61 and13. Thu all of the gear mechanisms on the shafts 44 and 45 remainstationary and are not driven under an idling condition. This is adecided advantage as it eliminates the 1oss .ofv any power and vibrationwhich might attend such rotation.

In the shifting of the gears in the transmission to the spindle, thegears which engage and disengage move toward and away from .each otherrather than having all the motion take place in a single gear. Thus, thegear 62 moves into and out of engagement with the gear 61 but the latteralso moves towards and away from the gear 62, this action being providedfor by the arms 64, 10, and '88. Furthermore, the

name's-ore provision of the sleeve I56 and gears I59 and Hill which arecarried thereby provide for two ratios in the drive to the gear I12Which is taken as the start of the tool feed. Thus, by shifting thesleeve !56 so that the gear 160 engages the gear 52 a low drive isprovided for coarse thread cutting.

Further definite advantages are presented by the interlock mechanism. Itis impossible to shift the gears without first depressing the button I09to shift the shaft 9| but this latter action cannot take place until therheostat 92 has been adjusted to low speed.

By providing for a gear reduction between the operating ring I25.and thepointer !33, it is possible to maintain a 1 to 1 ratio between the ringI25 and the rheostat control shaft 93 and yet have the pointer 533 moveover an entire range of only 120 degrees. Furthermore, by providin thestep up gearing between the gear shift lever '55 and the dial i4!movement of the gear shift lever is restricted to about 85 degrees toeach side of the vertical position illustrated while the dial is rotatedsufficiently far to bring the correct section to the uppermost positionwhere it cooperates with the pointer I33 to indicate the speed at whichthe spindle is being driven.

While a preferred specific embodiment of the invention is hereinbeforeset forth, it is to be clearly understood that the invention is not tobe limited to the exact mechanism, devices, apparatus, speeds, andhorsepower illustrated and described because various modifications ofthese details may be provided in putting the invention into practicewithin the purview of the appended claims.

What is claimed is:

1. In a lathe including a" work spindle to be driven and a variablespeed direct current motor as a power source, a transmission for drivingsaid spindle from said motor under different conditions of mechanicaladvantage, said transm s ion comprising a pulley freely journaled onsaid spindle, a clutch operable to d ivably connect said pulley to saidspindle, a back gear shaft, a pulley'drivably carried by said back gearshaft, a gear drivably and slidably mounted on said back gear shaft, acompound gear freely journaled on said back gear shaft and including agear element adapted to be engaged by said sliding gear, a gear trainproviding a predetermined gear ratio and adapted to be connected betweensaid sliding gear and said spindle, a second gear train of a differentratio adapted to be operatively connected between said com pound gearand said spindle, a drive shaft included as a part of said motor, apulley drivably carried by said drive s aft, and drive belt passing overall said pulleys.

2. In a lathe including a work spindle to be driven and a variable speeddirect current motor as a power source, a transmission for driving saidspindle from said motor under different conditions of mechanicaladvantage, said transmission comprising a pulley freely journaled onsaid spindle, a clutch operable to drivably connect said pulley to saidspindle, clutch operating means for establishing or disestablishin thedriving relation, a back gear shaft, a pulley drivably carried by saidback gear shaft, a gear drivably and slidably mounted on said gearshaft, means for shifting said gear, a compound gear freely journaled onsaid gear shaft and including a gear element adapted to be engaged'bysaid sliding gear, a gear train providing a predetermin d gear ratio andadapted to be conn cted between said sliding gear and said spindle, asecond gear train of a different ratio adapted to be operativelyconnected between said com ound gear and said spindle, a drive shaftincluded as a part of said motor, a pulley drivably carried by saiddrive shaft, a drive belt passing over all said pulleys, and mechanismfor interrelating the operations of said clutch operating means and saidgear shifting means.

3. In a lathe including a work spindle to be driven and a variable speeddirect current motor as a power source; a transmission for driving saidspindle from said motor under difierent conditions of mechanicaladvantage, said transmission comprising a pulley freely journaled onsaid spindle; a clutch operable to drivably connect said pulley to saidspindle; a back gear shaft; a pulley drivably carried by said back gearshaft; a gear drivably and slidably mounted on said back gear shaft; acompound gear freely journaled on said back gear shaft and including aninternal gear adapted to be engaged by said sliding gear, an externalgear, and a pinion of smaller diameter than said external gear; a pairof aligned counter shafts; a compound gear on one of said counter shaftsand includinga gear adapted to mesh with said sliding gear, and a pinionadapted to mesh with said external gear of the first said compound gear;and another compound gear on the other of said counter shafts, said lastmentioned compound gear having a gear slidably engaging the pinion ofthe first said compound gear, and a pinion that is adapted to bedrivably connected to said spindle; a drive shaft included as a part ofsaid motor; a pulley carried by said drive shaft; and a belt passingover all of said pulleys. A

4. In a lathe including a work spindle to be driven and a variable speeddirect current motor as a power source, a transmission for driving saidspindle from said motor under different conditions of mechanicaladvantage, said transmission comprising a pulley freely journaled onsaid spindle; a clutch operable to drivably con-- nect said pulley tosaid spindle; clutch o crating means; a back gear shaft; a pulleydrivably carried by said back gear shaft; a gear drivably and slidablymounted on said back gear shaft; means for shifting said gear; acompound gear freely journaled on said back gear shaft and including aninternal gear adapted to be engaged by said sliding gear, an externalgear, and a pinion of smaller diameter than said external gear; a pairof aligned counter shafts; a compound gear on one of said counter shaftsand including a gear adapted to mesh with said sliding gear, and apinion adapted to mesh with said external gear of the first saidcompound gear; means for shifting said last mentioned compound gear onsaid countershaft; and another compound gear on the other of saidcounter shafts, said last mentioned compound gear having a gear slidablyengaging the pinion of the first said compound gear and a pinion that isadapted to be drivably connected to said spindle; gear shifting meansfor shifting the last said compound gear; a drive shaft included as apart of said motor, a pulley carried by said drive shaft; a belt passingover all of said pulleys; and mechanism for interrelating the operationsof said clutch operating and all said gear shifting means.

5. In a lathe including a variable speed motor,

'- a rheostat associated with said motor to control the speed thereof,and a change gear transmission adapted to provide different speedrangesin the transmission of power from said motor, a sleeve rotatably mountedand operatively connected to said transmission to cause a shifting ofthe gears thereof upon rotation of said sleeve, a shaft enclosed by saidsleeve and longitudinally movable and rotatable therein, releasablemeans for locking said sleeve in an angular position of adjustment, saidreleasable means being connected to said shaft to be released uponlongitudinal movement thereof, operative connections between. said shaftand said rheostat whereby rotation of said shaft adjusts said rheostat,and an interlock for permitting longitudinal movement of said shaft onlywhen it is in a position that adjusts said rheostat for the low speedoperation of said motor.

6. In a lathe including a variable speed motor,

a rheostat associated with said motor to control the speed thereof, anda change gear transmission adapted to provide different speed ranges inthe transmission of power from said motor,

' a sleeve rotatably mounted and operatively connected to saidtransmission to cause a shifting of the gears thereof upon rotation ofsaid sleeve, a gear shift lever radially outstanding from said sleeve, ashaft enclosed by said sleeve and longitudinally movable and rotatabletherein, releasable means for locking said sleeve in an angular positionof adjustment, said releasable means being connected to said shaft to bereleased upon longitudinal movement thereof, spring means normallyurging said shaft 'in one direction, a

; knob at one end of said shaft adapted to move it in the otherdirection against the influence of said spring means, operativeconnections between said shaft and said rheostat whereby rotation ofsaid shaft adjusts said rheostat, an operating member drivably connectedto said shaft for rotation thereof, and an interlock for permittinglongitudinal movement of said shaft only when it is in a position thatadjusts said rheostat for the low speed operation of said motor.

7. In a lathe including a work spindle and a drive for a tool feed,mechanism selectively operable to operate said tool feed drive from saidspindle and comprising a first compound gear slidably and drivablymounted on said spindle I and including a pair of gear elements of different diameters, a countershaft mounted substantially parallel to saidspindle, a second compound gear slidably and drivably mounted on saidcountershaft comprising a gear element on said second compound gearoperatively connected to said tool feed drive and a second gear elementon said second compound gear of smaller diametenand means for shiftingboth of said compound-gears-to engage'said gear elements to provide twodifferent operating gear ratios between said spindle and said tool feeddrive.

8. In a lathe including a work spindle and a drive for a tool feed,mechanism selectively operable to operate said tool feed drive from saidspindle and comprising a first compound gear slidably and drivablymounted on said spindle and including a pair of gear elements ofdifferent diameters, means for shifting said gear longitudinally on saidspindle, a countershaft mounted substantially parallel to said spindle,a second compound gear slidably and drivably mounted on saidcountershaft comprising a gear element on said second compound gearoperatively connected to said tool feed drive and a second gear elementon said second compound gear of smaller diameter, and means for shiftingboth of said compound gears to engage said gear elements to provide twodifferent operating gear ratios between said spindle and said tool feeddrive including one shifting means for shifting the second of saidcompound-gears on saidcountershaft, and another shifting meansinteracting with said one shifting means to shift the first compoundgear on said spindle.

9. In a lathe including a work spindle and a drive for a tool feed,mechanism selectively op- P erable to operate said tool feed drive fromsaid spindle and comprising a compound gear slidably keyed to saidspindle and including a pinion at one end and a gear of larger diameterthan said pinionat the other end, a splined countershaft arrangedsubstantially parallel to said spindle, a second compound gear includinga gear at the end corresponding to the pinion on the first compound gearand adapted to mesh therewith, a pinion on the other end of said secondcompound gear adapted to mesh with the gear on the first said compoundgear, the gear on said second compound gear being operatively connectedto said tool feed drive, and an internal gear at one end thereof, athird compoundgear freely journaled on said countershaft and includingan externally toothed pinion adapted to mesh with said internal gear,and a gear element drivably connected to a source of power other thansaid spindle, and means for shifting the second said compound gear tocause it to take power either from said spindle or the third saidcompound gear.

HAROLD J. SIEKMANN. GEORGE J. KASSELMANN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,156,596 Lloyd May 2, 19392,197,893 Le Blond Apr. 23, 1940 2,221,574 Chladek Nov. 12, 19402,332,381 Hollscher Oct; 19, 1943 2,387,417 Sundt Oct. 24, 19452,419,639 Groene Apr. 29, 1947

